This section is intended to introduce various aspects of the art, which may be associated with exemplary embodiments of the present techniques. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present techniques. Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art.
Any of a number of subsea separation techniques may be used to enhance the amount of oil and gas recovered from subsea wells. However, subsea separation at water depths greater than 1500 meters becomes especially challenging due to the environmental conditions. As water depth increases, the external pressure on a vessel created by the hydrostatic head increases the required wall thickness for vessels used for subsea processing. At water depths greater than 1500 meters, this wall thickness increases to such an extent that typical gravity separation vessels are not practical. In addition, vessels with such a large wall thickness can be a challenge to fabricate, and the added material and weight can impact project economics, as well as the retrievability of the vessel for maintenance. As a result, large diameter separators often cannot be used at such water depths.
Studies have been done concerning liquid and gas separation in subsea systems and methods in U.S. Pat. No. 8,282,711B2. These systems and methods describe the separation of liquids and gases from a subsea production fluid, using a pipe system that splits the flows of the liquid and gaseous fluids through separate manifolds.
Additional studies concerning a pipe separator system for improving separation may be found in U.S. Pat. No. 7,490,671. The system describes a pipe separator, which utilizes a cyclone and an electrostatic coalescer as part of the separator body, for separation of oil, gas, and water originating from a subsea well.
Additional studies concerning a pipe separator for the separation of fluids may be found in U.S. Pat. No. 7,516,794. This system describes a pipe system similar to that in U.S. Pat. No. 7,490,671, and flows fluids into separate pipe manifolds. The pipe system described adds the requirement that the system be “piggable”.
Additional studies concerning an installation for the separation of fluids may be found in U.S. Application 2005/0006086. The system describes pipe separators that form a part of the transport pipeline, and that utilize an electrostatic coalescer to separate an oil, gas, and water stream.
Additional studies concerning a method and apparatus for improving the performance of a separator may be found in U.S. Application 2008/0116072. The method and apparatus describe a gravity settling vessel, and feeding an off-take stream through a compact electrostatic coalescer and back into the settling vessel.